Intelligent transport systems -- Low-speed automated driving (LSAD) systems for predefined routes -- Performance requirements, system requirements and performance test procedures

This document specifies: —   requirements for the operational design domain, —   system requirements, —   minimum performance requirements, and —   performance test procedures for the safe operation of low-speed automated driving (LSAD) systems for operation on predefined routes. LSAD systems are designed to operate at Level 4 automation (see ISO/SAE PAS 22736), within specific operational design domains (ODD). This document applies to automated driving system-dedicated vehicles (ADS-DVs) and can also be utilized by dual-mode vehicles (see ISO/SAE PAS 22736). This document does not specify sensor technology present in vehicles driven by LSAD systems.

Systèmes de transport intelligents -- Systèmes de conduite automatisée à basse vitesse pour des itinéraires prédéfinis (LSAD) -- Exigences de performance, exigences du système et procédures de test de performance

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Status
Published
Publication Date
05-Jul-2021
Current Stage
5060 - Close of voting Proof returned by Secretariat
Start Date
01-Jun-2021
Completion Date
01-Jun-2021
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INTERNATIONAL ISO
STANDARD 22737
First edition
2021-07
Intelligent transport systems — Low-
speed automated driving (LSAD)
systems for predefined routes —
Performance requirements, system
requirements and performance test
procedures
Systèmes de transport intelligents — Systèmes de conduite
automatisée à basse vitesse pour des itinéraires prédéfinis (LSAD) —
Exigences de performance, exigences du système et procédures de test
de performance
Reference number
ISO 22737:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO 22737:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 22737:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 3

5 Example use case for an LSAD system deployment .......................................................................................................... 4

6 LSAD system architecture ........................................................................................................................................................................... 5

7 Basic requirements ............................................................................................................................................................................................ 6

7.1 General ........................................................................................................................................................................................................... 6

7.2 Minimum operating capabilities .............................................................................................................................................. 7

7.3 Operational design domains (ODDs) ................................................................................................................................... 7

7.4 LSAD state transition diagram ................................................................................................................................................... 7

7.4.1 LSAD state functional descriptions .................................................................................................................. 8

7.4.2 LSAD state transition description: .................................................................................................................... 9

7.4.3 Possible extension of the LSAD state diagram to accommodate dispatcher

inputs ......................................................................................................................................................................................11

7.5 Communication requirements ...............................................................................................................................................11

8 Functional requirements ..........................................................................................................................................................................12

8.1 Determination of hazardous situation ............................................................................................................................12

8.1.1 General...................................................................................................................................................................................12

8.1.2 Non-occluded view .....................................................................................................................................................12

8.1.3 Occluded view .................................................................................................................................................................13

8.2 Minimal risk manoeuvre (MRM) ..........................................................................................................................................14

8.3 Driving in the drivable area ......................................................................................................................................................15

8.4 Emergency stop (e-stop) .............................................................................................................................................................15

9 Performance requirements for the LSAD system ............................................................................................................16

9.1 Maximum subject vehicle speed (V ) ...................................................................................................................16

SV_max

9.2 Obstacle detection requirements .........................................................................................................................................16

9.2.1 Maximum pedestrian speed (V ) .....................................................................................................16

ped_max

9.2.2 Maximum pedal cyclist speed (V ) ....................................................................................................16

pc_max

9.2.3 LSAD system deceleration ....................................................................................................................................16

10 System requirements ....................................................................................................................................................................................16

10.1 Recording data about a safety-critical event ..............................................................................................................16

11 Performance test procedures ...............................................................................................................................................................17

11.1 General ........................................................................................................................................................................................................17

11.2 Environmental parameters .......................................................................................................................................................17

11.3 Hazardous situation ........................................................................................................................................................................18

11.3.1 Pedestrian as an obstacle ......................................................................................................................................18

11.3.2 Pedal cyclist as an obstacle ..................................................................................................................................20

11.3.3 Hazardous situation turning around a corner ....................................................................................23

11.3.4 False positive tests.......................................................................................................................................................24

11.4 Drivable area test ...............................................................................................................................................................................26

11.4.1 Test setup ............................................................................................................................................................................26

11.4.2 Vehicle parameters .....................................................................................................................................................27

11.4.3 Evaluation path parameters ................................................................................................................................27

11.4.4 Environmental parameters ..................................................................................................................................27

11.4.5 Pass criteria for unblocked drivable area ................................................................................................27

11.4.6 Pass criteria for blocked drivable area ......................................................................................................28

11.5 Minimal risk manoeuvre (MRM) test................................................................................................................................28

© ISO 2021 – All rights reserved iii
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ISO 22737:2021(E)

11.5.1 Test setup ............................................................................................................................................................................28

11.5.2 Vehicle parameters .....................................................................................................................................................29

11.5.3 Evaluation path parameters ................................................................................................................................29

11.5.4 Environmental parameters ..................................................................................................................................29

11.5.5 MRM trigger ......................................................................................................................................................................30

11.5.6 Pass criteria .......................................................................................................................................................................30

Annex A (informative) Test speeds for hazardous situation tests ......................................................................................31

Annex B (informative) Example LSAD communication messages .......................................................................................33

Annex C (informative) Example LSAD system data recorder ...................................................................................................34

Annex D (informative) LSAD system activities (experiment tests) in various countries ............................35

Bibliography .............................................................................................................................................................................................................................43

iv © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 22737:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 204, Intelligent transport systems.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2021 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO 22737:2021(E)
Introduction

The move towards automated driving systems is leading to a shift in the way people, goods and

services are transported. One such new mode of transport is low-speed automated driving (LSAD)

systems, which operate on predefined routes. LSAD systems will be used for applications like last-mile

transportation, transport in commercial areas, business or university campus areas and other low-

speed environments.

A vehicle that is driven by the LSAD system (which can include interaction with infrastructure) can

potentially have many benefits, like providing safe, convenient and affordable mobility and reducing

urban congestion. It can also provide increased mobility for people who are not able to drive. However,

with different applications of LSAD systems in the industry worldwide, there is a need to provide

guidance for manufacturers, operators, end users and regulators to ensure their safe deployment.

The LSAD system requirements and procedures specified herein are intended to assist manufacturers

of the LSAD systems in incorporating minimum safety requirements into their designs and to allow

end users, operators and regulators to reference a minimum set of performance requirements in their

procurements.
vi © ISO 2021 – All rights reserved
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INTERNATIONAL STANDARD ISO 22737:2021(E)
Intelligent transport systems — Low-speed automated
driving (LSAD) systems for predefined routes —
Performance requirements, system requirements and
performance test procedures
1 Scope
This document specifies:
— requirements for the operational design domain,
— system requirements,
— minimum performance requirements, and
— performance test procedures

for the safe operation of low-speed automated driving (LSAD) systems for operation on predefined

routes. LSAD systems are designed to operate at Level 4 automation (see ISO/SAE PAS 22736), within

specific operational design domains (ODD).

This document applies to automated driving system-dedicated vehicles (ADS-DVs) and can also be

utilized by dual-mode vehicles (see ISO/SAE PAS 22736). This document does not specify sensor

technology present in vehicles driven by LSAD systems.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 19206-2, Road vehicles — Test devices for target vehicles, vulnerable road users and other objects, for

assessment of active safety functions — Part 2: Requirements for pedestrian targets

ISO 19206-3, Road vehicles — Test devices for target vehicles, vulnerable road users and other objects, for

assessment of active safety functions — Part 3: Requirements for passenger vehicle 3D targets

ISO 19206-4, Road vehicles — Test devices for target vehicles, vulnerable road users and other objects, for

assessment of active safety functions — Part 4: Requirements for bicyclist targets

ISO 26262 (all parts), Road vehicles — Functional safety
ISO 21448:— , Road vehicles — Safety of the intended functionality

ISO/SAE PAS 22736:— , Taxonomy and definitions for terms related to driving automation systems for

on-road motor vehicles
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/SAE PAS 22736 and the

following apply.
1) Under preparation. Stage at the time of publication: ISO/DIS 21448:2021.

2) Under preparation. Stage at the time of publication: ISO/SAE PRF PAS 22736:2021.

© ISO 2021 – All rights reserved 1
---------------------- Page: 7 ----------------------
ISO 22737:2021(E)

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
hazardous situation

condition whereby the position, orientation and motion of an obstacle (e.g. pedal cyclists, pedestrians,

vehicles, etc.) relative to the position, orientation and motion of the vehicle driven by the LSAD system,

can result in an imminent collision
3.2
predefined route

trajectory defined before start of a trip to be traversed by the vehicle driven by the LSAD system, from

a point of origin to one (or many) destination(s)

Note 1 to entry: A single trip of a vehicle driven by the LSAD system may have many destinations. A predefined

route has a length and curvature but not width.
3.3
minimal risk manoeuvre
MRM

tactical or operational manoeuvre triggered and executed by the LSAD system to achieve minimal risk

condition
3.4
trip segment

travel from point of origin to destination or from one destination to another destination in a trip

Note 1 to entry: A trip may comprise multiple trip segments.
3.5
drivable area

manoeuvrable area around the predefined route (3.2) where the LSAD system is capable of operating

Note 1 to entry: The width of the drivable area may vary along the predefined route.

3.6
pedal cyclist

human-vehicle combination consisting of a human riding on top of a wheel frame with a steering

mechanism, brakes, two pedals for propulsion (optionally with motor assist pedalling) that does not

require a licence for use on public roads
3.7
day-time
condition where the ambient illuminance is greater than 2 000 lx
3.8
night-time
condition where the ambient illuminance is less than 1 lx
3.9
standstill
vehicle state when vehicle speed is at 0 m/s
3.10
low-speed automated driving systems
LSAD
automated driving system that has a maximum speed of 8,89 m/s
2 © ISO 2021 – All rights reserved
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ISO 22737:2021(E)
3.11
low ambient lighting condition
ambient light between day-time (3.7) and night-time (3.8)
4 Symbols and abbreviated terms

ϴ angle between pedestrian trajectory and vehicle trajectory while in straight section of the

evaluation path
ADS-DV automated driving system-dedicated vehicle
DDT dynamic driving task
e-stop emergency stop
LSAD low-speed automated driving
MaaS mobility as a service
MRC minimal risk condition
ODD operational design domain
R radius of curvature of trajectory in drivable area
RTI request to intervene
S width of drivable area
lat1
S lateral distance between SV and pedestrian starting point
lat2
S lateral distance between SV and target vehicles (TV and TV )
lat3 1 2
S width of reduced drivable area
lat4
S longitudinal distance of drivable area
long
S longitudinal distance of evaluation path from situation C
long2
S longitudinal distance between point 1 and point 4
long3
S longitudinal distance between point 1 and point 4 where MRM is triggered
long4
S longitudinal distance between point 4 and end of evaluation path
long5
SV subject vehicle
T time taken by pedestrian to reach point 2
ped_to_Pt2
T time taken by pedal cyclist to reach point 2
pc_to_Pt2
TV target vehicle (1, 2)
(1, 2)
V2X vehicle to - X
V velocity for the LSAD system
LSAD
V maximum velocity for the LSAD system
LSAD_max
V velocity of pedal cyclist
© ISO 2021 – All rights reserved 3
---------------------- Page: 9 ----------------------
ISO 22737:2021(E)
V maximum velocity of pedal cyclist
pc_max
V velocity of pedestrian
ped
V maximum velocity of pedestrian
ped_max
V maximum velocity of subject vehicle
sv_max
VRU vulnerable road users
DDT dynamic driving task
5 Example use case for an LSAD system deployment

Vehicles driven by LSAD systems may be used as a part of a larger (MaaS) system. Figure 1 depicts an

example system architecture of such a MaaS system. However, the scope of this document is restricted

to the LSAD system installed in a vehicle in Figure 1.

As per the example in Figure 1, the LSAD system receives a trip destination from the dispatcher via

wireless communication, which in turn receives a destination request from the user (through a web

portal or a mobile app. The dispatcher or the control centre processes the destination request and

provides a trip/trip segment confirmation to the user and commands the vehicle driven by the LSAD

system to proceed. The term "dispatcher" in this document refers to the driverless operation dispatcher

(see ISO/SAE PAS 22736).

As there may be more than one predefined route to reach the destination, the selected predefined route

may be:
1) provided by the dispatcher/control centre;

2) selected by the user via a user-interface on a mobile app or on-board the LSAD system equipped

vehicle;
3) selected by the LSAD system itself.

The LSAD system periodically provides its status (e.g. system health, trip status) to the user and the

dispatcher/control server.
4 © ISO 2021 – All rights reserved
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ISO 22737:2021(E)
Figure 1 — Example system architecture — LSAD in a MaaS system
6 LSAD system architecture

Figure 2 represents the system architecture of an individual LSAD system. Figure 2 also highlights the

components from the LSAD system architecture that are covered within the scope of this document.

© ISO 2021 – All rights reserved 5
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ISO 22737:2021(E)
Key
functional requirements defined in this document
optional features not defined in this document
functional requirements not defined in this document
Figure 2 — Example system architecture — Individual LSAD system
7 Basic requirements
7.1 General

The LSAD system shall perform the dynamic driving task (see ISO/SAE PAS 22736). The implementation

of the strategic driving tasks (see ISO/SAE PAS 22736) is left to the manufacturer’s discretion. However,

the LSAD system shall operate in predefined routes only. The maximum operational speed of an

LSAD system engaged vehicle shall be equal to or less than 8,89 m/s or 32 km/h. However, this may

be significantly reduced based on special conditions (selected as per the discretion of the driverless

operation dispatcher [ISO/SAE PAS 22736]) mentioned in this document, for example time of day,

visibility, day of week, rainfall, snow, fog, ice on roads etc.).

The LSAD system shall use sensors in order to enable part of the dynamic driving task. This includes

detecting objects, vehicles, pedestrians, buildings, pathways, etc. Appropriate hazard analysis and

risk assessment shall be performed for the sensor performance and failures, and other safety critical

system elements. The LSAD system development shall be developed according to the ISO 26262 series

and ISO 21448.
6 © ISO 2021 – All rights reserved
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ISO 22737:2021(E)
7.2 Minimum operating capabilities

Subject vehicles driven by the LSAD system shall be capable of performing the following functions:

a) follow a predefined route to the destination (8.3),
b) detect a hazardous situation (8.1),

c) initiate braking and/or steering, to mitigate and/or avoid collision with obstacles (9.1, 9.2),

d) perform minimal risk manoeuvre (8.2),

e) inform the dispatcher about the fault state of the LSAD system (e.g. binary flag) (8.4),

f) provide warnings to road users in case of a hazardous situation.
7.3 Operational design domains (ODDs)

Every LSAD system shall have its ODD defined by the manufacturer. The ODD limitations for an LSAD

system shall specify at least the following attributes:

a) Low speed: the speed of an LSAD system shall be equal to or less than 8,89 m/s or 32 km/h.

b) Areas of application: for example, either restricted access or dedicated roadways (public or

private), or pedestrian/bicycle pathways, or areas from which all or some specific categories of

motor vehicles are restricted. Restricted access roadways can be specified by lane markings or

speed restriction or physical demarcation. (See Annex D for examples).

c) Predefined routes: routes defined within the LSAD system before operation of the LSAD system.

An LSAD system shall only operate on the predefined routes. Predefined routes shall be defined

by relevant stakeholders in conjunction with each other (e.g. local authorities, service providers,

manufacturers, etc.). Any deviation from predefined routes shall be confirmed by the dispatcher to

not result in a hazardous situation.
d) Lighting conditions in the area of application.
e) Weather conditions.
f) Road conditions.
g) Presence or absence of VRUs.
h) Potential presence of static obstacles in the drivable area.
i) Connectivity requirements.

Either the LSAD systems or the dispatcher should select operating values (for a vehicle driven by the

LSAD system) within the boundaries of the predefined values of the ODD attributes for the specified

application based on current ODD conditions (e.g. foggy weather conditions, night-time lighting

conditions).

EXAMPLE A dispatcher or an LSAD system can decide to restrict the maximum allowable speed on a rainy

day to a lower speed as compared to a clear, sunny day.
7.4 LSAD state transition diagram

The LSAD system shall function according to the state transition diagram of Figure 3. Specific

implementation, beyond the description in Figure 3 shall be the responsibility of the manufacturer.

© ISO 2021 – All rights reserved 7
---------------------- Page: 13 ----------------------
ISO 22737:2021(E)
Key
A1 power on and self-test passed
B1 system failure or power-off dispatcher command or power turned off

B2 ODD conditions are met and dispatcher has sent engage ADS command and ADS equipped vehicle has data

recording capability and has engaged it
C1 dispatcher disengage command
C2 passenger or dispatcher initiates emergency stop

C3 detection of hazardous situation which the LSAD system is unable to handle or DDT performance relevant

system failure or loss of safety critical V2X communications or imminent violation of ODD or safe to proceed

confirmation authorization not received from dispatcher
C4 vehicle is in standstill, i.e. 0 m/s
C5 confirmation to proceed to standby state by dispatcher

C6 vehicle is in standstill, i.e. 0 m/s, and confirmation to proceed to standby state by dispatcher

Figure 3 — LSAD state transition diagram
7.4.1 LSAD state functional descriptions
7.4.1.1 LSAD off

The LSAD system shall not perform any aspect of the dynamic driving task in the LSAD off state.

8 © ISO 2021 – All rights reserved
---------------------- Page: 14 ----------------------
ISO 22737:2021(E)
7.4.1.2 LSAD standby
In LSAD standby state, the LSAD system shall:

a) Verify that ODD conditions are satisfied to enable a transition to LSAD active state.

b) Perform communications with dispatcher.
c) Remain in standstill.

LSAD standby state may receive an external operating command from the dispatcher selecting the

operating values (e.g. nominal or degraded) for the LSAD system when in DDT state.

Note that nominal mode suggests the ideal performance of the vehicle driven by the LSAD system.

Degraded mode suggests reduced performance on pre-defined vehicle parameters due to external or

the LSAD system’s internal conditions.
7.4.1.3 LSAD active
In LSAD
...

INTERNATIONAL ISO
STANDARD 22737
First edition
Intelligent transport systems — Low-
speed automated driving (LSAD)
systems for predefined routes —
Performance requirements, system
requirements and performance test
procedures
Systèmes de transport intelligents — Systèmes de conduite
automatisée à basse vitesse pour des itinéraires prédéfinis (LSAD) —
Exigences de performance, exigences du système et procédures de test
de performance
PROOF/ÉPREUVE
Reference number
ISO 22737:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO 22737:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 22737:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 3

5 Example use case for an LSAD system deployment .......................................................................................................... 4

6 LSAD system architecture ........................................................................................................................................................................... 5

7 Basic requirements ............................................................................................................................................................................................ 6

7.1 General ........................................................................................................................................................................................................... 6

7.2 Minimum operating capabilities .............................................................................................................................................. 7

7.3 Operational design domains (ODDs) ................................................................................................................................... 7

7.4 LSAD state transition diagram ................................................................................................................................................... 7

7.4.1 LSAD state functional descriptions .................................................................................................................. 8

7.4.2 LSAD state transition description: .................................................................................................................... 9

7.4.3 Possible extension of the LSAD state diagram to accommodate dispatcher

inputs ......................................................................................................................................................................................11

7.5 Communication requirements ...............................................................................................................................................11

8 Functional requirements ..........................................................................................................................................................................12

8.1 Determination of hazardous situation ............................................................................................................................12

8.1.1 Non-occluded view .....................................................................................................................................................12

8.1.2 Occluded view .................................................................................................................................................................13

8.2 Minimal risk manoeuvre (MRM) ..........................................................................................................................................14

8.3 Driving in the drivable area ......................................................................................................................................................14

8.4 Emergency stop (e-stop) .............................................................................................................................................................15

9 Performance requirements for the LSAD system ............................................................................................................16

9.1 Maximum subject vehicle speed (V ) ...................................................................................................................16

SV_max

9.2 Obstacle detection requirements .........................................................................................................................................16

9.2.1 Maximum pedestrian speed (V ) .....................................................................................................16

ped_max

9.2.2 Maximum pedal cyclist speed (V ) ....................................................................................................16

ps_max

9.2.3 LSAD system deceleration ....................................................................................................................................16

10 System requirements ....................................................................................................................................................................................16

10.1 Recording data about a safety-critical event ..............................................................................................................16

11 Performance test procedures ...............................................................................................................................................................17

11.1 General ........................................................................................................................................................................................................17

11.2 Environmental parameters .......................................................................................................................................................17

11.3 Hazardous situation ........................................................................................................................................................................17

11.3.1 Pedestrian as an obstacle ......................................................................................................................................17

11.3.2 Pedal cyclist as an obstacle ..................................................................................................................................19

11.3.3 Hazardous situation turning around a corner ....................................................................................22

11.3.4 False positive tests.......................................................................................................................................................24

11.4 Drivable area test ...............................................................................................................................................................................26

11.4.1 Test setup ............................................................................................................................................................................26

11.4.2 Vehicle parameters .....................................................................................................................................................27

11.4.3 Evaluation path parameters ................................................................................................................................27

11.4.4 Environmental parameters ..................................................................................................................................28

11.4.5 Pass criteria for unblocked drivable area ................................................................................................28

11.4.6 Pass criteria for blocked drivable area ......................................................................................................28

11.5 Minimal risk manoeuvre (MRM) test................................................................................................................................28

11.5.1 Test setup ............................................................................................................................................................................28

© ISO 2021 – All rights reserved PROOF/ÉPREUVE iii
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ISO 22737:2021(E)

11.5.2 Vehicle parameters .....................................................................................................................................................29

11.5.3 Evaluation path parameters ................................................................................................................................29

11.5.4 Environmental parameters ..................................................................................................................................29

11.5.5 MRM trigger ......................................................................................................................................................................30

11.5.6 Pass criteria .......................................................................................................................................................................30

Annex A (informative) Test speeds for hazardous situation tests ......................................................................................31

Annex B (informative) Example LSAD communication messages .......................................................................................33

Annex C (informative) Example LSAD system data recorder ...................................................................................................34

Annex D (informative) LSAD system activities (experiment tests) in various countries ............................35

Bibliography .............................................................................................................................................................................................................................43

iv PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 22737:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 204, Intelligent transport systems.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO 22737:2021(E)
Introduction

The move towards automated driving systems is leading to a shift in the way people, goods and

services are transported. One such new mode of transport is low-speed automated driving (LSAD)

systems, which operate on predefined routes. LSAD systems will be used for applications like last-mile

transportation, transport in commercial areas, business or university campus areas and other low-

speed environments.

A vehicle that is driven by the LSAD system (which can include interaction with infrastructure) can

potentially have many benefits, like providing safe, convenient and affordable mobility and, reducing

urban congestion. It can also provide increased mobility for people who are not able to drive. However,

with different applications of LSAD systems in the industry worldwide, there is a need to provide

guidance for manufacturers, operators, end users and regulators to ensure their safe deployment.

The LSAD system requirements and procedures specified herein are intended to assist manufacturers

of the LSAD systems in incorporating minimum safety requirements into their designs and to allow

end users, operators and regulators to reference a minimum set of performance requirements in their

procurements.
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INTERNATIONAL STANDARD ISO 22737:2021(E)
Intelligent transport systems — Low-speed automated
driving (LSAD) systems for predefined routes —
Performance requirements, system requirements and
performance test procedures
1 Scope
This document specifies:
— requirements for the operational design domain,
— system requirements,
— minimum performance requirements, and
— performance test procedures

for the safe operation of low-speed automated driving (LSAD) systems for operation on predefined

routes. LSAD systems are designed to operate at Level 4 automation (see ISO/SAE DPAS 22736), within

specific operational design domains (ODD).

This document applies to automated driving system-dedicated vehicles (ADS-DVs) and can also be

utilized by dual-mode vehicles (see ISO 2575). This document does not specify sensor technology

present in vehicles driven by LSAD systems.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 19206-2, Road vehicles — Test devices for target vehicles, vulnerable road users and other objects, for

assessment of active safety functions — Part 2: Requirements for pedestrian targets

ISO 19206-3, Road vehicles — Test devices for target vehicles, vulnerable road users and other objects, for

assessment of active safety functions — Part 3: Requirements for passenger vehicle 3D targets

ISO 19206-4, Road vehicles — Test devices for target vehicles, vulnerable road users and other objects, for

assessment of active safety functions — Part 4: Requirements for bicyclist targets

ISO 26262 (all parts), Road vehicles — Functional safety
ISO 21448:— , Road vehicles — Safety of the intended functionality

ISO/SAE DPAS 22736:— , Taxonomy and definitions for terms related to driving automation systems for

on-road motor vehicles
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/SAE DPAS 22736 and the

following apply.
1) Under preparation. Stage at the time of publication: ISO/DIS 21448:2021.

2) Under preparation. Stage at the time of publication: ISO/SAE DPAS 22736:2021.

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ISO 22737:2021(E)

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
hazardous situation

condition whereby the position, orientation and motion of an obstacle (e.g. pedal cyclists, pedestrians,

vehicles, etc.) relative to the position, orientation and motion of the vehicle driven by the LSAD system,

can result in an imminent collision
3.2
predefined route

trajectory defined before start of a trip to be traversed by the vehicle driven by the LSAD system, from

a point of origin to one (or many) destination(s)

Note 1 to entry: A single trip of a vehicle driven by the LSAD system may have many destinations. A predefined

route has a length and curvature but not width.
3.3
minimal risk manoeuvre
MRM

tactical or operational manoeuvre triggered and executed by the LSAD system to achieve minimal risk

condition
3.4
trip segment

travel from point of origin to destination or from one destination to another destination in a trip

Note 1 to entry: A trip may comprise multiple trip segments.
3.5
drivable area

manoeuvrable area around the predefined route (3.2) where the LSAD system is capable of operating

Note 1 to entry: The width of the drivable area may vary along the predefined route.

3.6
pedal cyclist

human-vehicle combination consisting of a human riding on top of a wheel frame with a steering

mechanism, brakes, two pedals for propulsion (optionally with motor assist pedalling) that does not

require a licence for use on public roads
3.7
day-time
condition where the ambient illuminance is greater than 2 000 lx
3.8
night-time
condition where the ambient illuminance is less than 1 lx
3.9
standstill
vehicle state when vehicle speed is at 0 m/s
3.10
low-speed automated driving systems
LSAD
automated driving system that has a maximum speed of 8,89 m/s
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ISO 22737:2021(E)
3.11
low ambient lighting condition
ambient light between day-time (3.7) and night-time (3.8)
4 Symbols and abbreviated terms

ϴ angle between pedestrian trajectory and vehicle trajectory while in straight section of the

evaluation path
ADS-DV automated driving system-dedicated vehicle
DDT dynamic driving task
e-stop emergency stop
LSAD low-speed automated driving
MaaS mobility as a service
MRC minimal risk condition
ODD operational design domain
R radius of curvature of trajectory in drivable area
RTI request to intervene
S width of drivable area
lat1
S lateral distance between SV and pedestrian starting point
lat2
S lateral distance between SV and target vehicles (TV and TV )
lat3 1 2
S width of reduced drivable area
lat4
S longitudinal distance of drivable area
long
S longitudinal distance of evaluation path from situation C
long2
S longitudinal distance between point 1 and point 4
long3
S longitudinal distance between point 1 and Pt.4 where MRM is triggered
long4
S longitudinal distance between Pt. 4 and end of evaluation path
long5
SV subject vehicle
T time taken by pedestrian to reach point 2
ped_to_Pt2
T time taken by pedal cyclist to reach point 2
pc_to_Pt2
TV target vehicle (1, 2)
(1, 2)
V2X vehicle to - X
V velocity for the LSAD system
LSAD
V maximum velocity for the LSAD system
LSAD_max
V velocity of pedal cyclist
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ISO 22737:2021(E)
V maximum velocity of pedal cyclist
pc_max
V velocity of pedestrian
ped
V velocity of pedestrian
ped_max
V maximum velocity of subject vehicle
sv_max
VRU vulnerable road users
DDT dynamic driving task
5 Example use case for an LSAD system deployment

Vehicles driven by LSAD systems may be used as a part of a larger (MaaS) system. Figure 1 depicts an

example system architecture of such a MaaS system. However, the scope of this document is restricted

to the LSAD system installed in a vehicle in Figure 1.

As per the example in Figure 1, the LSAD system receives a trip destination from the dispatcher via

wireless communication, which in turn receives a destination request from the user (through a web

portal or a mobile app. The dispatcher or the control centre processes the destination request and

provides a trip/trip segment confirmation to the user and commands the vehicle driven by the LSAD

system to proceed. The term "dispatcher" in this document refers to the driverless operation dispatcher

(see ISO/SAE DPAS 22736).

As there may be more than one predefined route to reach the destination, the selected predefined route

may be:
1) provided by the dispatcher/control centre;

2) selected by the user via a user-interface on a mobile app or on-board the LSAD system equipped

vehicle;
3) selected by the LSAD system itself.

The LSAD system periodically provides its status (e.g. system health, trip status) to the user and the

dispatcher/control server.
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ISO 22737:2021(E)
Figure 1 — Example system architecture — LSAD in a MaaS system
6 LSAD system architecture

Figure 2 represents the system architecture of an individual LSAD system. Figure 2 also highlights the

components from the LSAD system architecture that are covered within the scope of this document.

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ISO 22737:2021(E)
Key
functional requirements defined in this document
optional features not defined in this document
functional requirements not defined in this document
Figure 2 — Example system architecture — individual LSAD system
7 Basic requirements
7.1 General

The LSAD system shall perform the dynamic driving task (see ISO/SAE DPAS 22736). The implementation

of the strategic driving tasks (see ISO/SAE DPAS 22736) is left to the manufacturer’s discretion.

However, the LSAD system shall operate in predefined routes only. The maximum operational speed of

an LSAD system engaged vehicle shall be equal to or less than 8,89 m/s or 32 km/h. However, this may

be significantly reduced based on special conditions (selected as per the discretion of the driverless

operation dispatcher [ISO/SAE DPAS 22736]) mentioned in this document, for example time of day,

visibility, day of week, rainfall, snow, fog, ice on roads etc.).

The LSAD system shall use sensors in order to enable part of the dynamic driving task. This includes

detecting objects, vehicles, pedestrians, buildings, pathways, etc. Appropriate hazard analysis and

risk assessment shall be performed for the sensor performance and failures, and other safety critical

system elements. The LSAD system development shall be developed according to the ISO 26262 series

and ISO 21448.
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ISO 22737:2021(E)
7.2 Minimum operating capabilities

Subject vehicles driven by the LSAD system shall be capable of performing the following functions:

a) follow a predefined route to the destination (8.3),
b) detect a hazardous situation (8.1),

c) initiate braking and/or steering, to mitigate and/or avoid collision with obstacles (9.1, 9.2),

d) perform minimal risk manoeuvre (8.2),

e) inform the dispatcher about the fault state of the LSAD system (e.g. binary flag) (8.4),

f) provide warnings to road users in case of a hazardous situation.
7.3 Operational design domains (ODDs)

Every LSAD system shall have its ODD defined by the manufacturer. The ODD limitations for an LSAD

system shall specify at least the following attributes:

a) Low speed: the speed of an LSAD system shall be equal to or less than 8,89 m/s or 32 km/h.

b) Areas of application: for example, either restricted access or dedicated roadways (public or

private), or pedestrian/bicycle pathways, or areas from which all or some specific categories of

motor vehicles are restricted. Restricted access roadways can be specified by lane markings or

speed restriction or physical demarcation. (See Annex D for examples).

c) Predefined routes: routes defined within the LSAD system before operation of the LSAD system.

An LSAD system shall only operate on the predefined routes. Predefined routes shall be defined

by relevant stakeholders in conjunction with each other (e.g. local authorities, service providers,

manufacturers, etc.). Any deviation from predefined routes shall be confirmed by the dispatcher to

not result in a hazardous situation.
d) Lighting conditions in the area of application.
e) Weather conditions.
f) Road conditions.
g) Presence or absence of VRUs.
h) Potential presence of static obstacles in the drivable area.
i) Connectivity requirements.

Either the LSAD systems or the dispatcher should select operating values (for a vehicle driven by the

LSAD system) within the boundaries of the predefined values of the ODD attributes for the specified

application based on current ODD conditions (e.g. foggy weather conditions, night-time lighting

conditions).

EXAMPLE A dispatcher or an LSAD system can decide to restrict the maximum allowable speed on a rainy

day to a lower speed as compared to a clear, sunny day.
7.4 LSAD state transition diagram

The LSAD system shall function according to the state transition diagram of Figure 3. Specific

implementation, beyond the description in Figure 3 shall be the responsibility of the manufacturer.

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ISO 22737:2021(E)
Key
A1 power on and self-test passed
B1 system failure or power-off dispatcher command or power turned off

B2 ODD conditions are met and dispatcher has sent engage ADS command and ADS equipped vehicle has data

recording capability and has engaged it
C1 dispatcher disengage command
C2 passenger or dispatcher initiates emergency stop

C3 detection of hazardous situation which the LSAD system is unable to handle or DDT performance relevant

system failure or loss of safety critical V2X communications or imminent violation of ODD or safe to proceed

confirmation authorization not received from dispatcher
C4 vehicle is in standstill, i.e. 0 m/s
C5 confirmation to proceed to standby state by dispatcher

C6 vehicle is in standstill, i.e. 0 m/s, and confirmation to proceed to standby state by dispatcher

Figure 3 — LSAD state transition diagram
7.4.1 LSAD state functional descriptions
7.4.1.1 LSAD off

The LSAD system shall not perform any aspect of the dynamic driving task in the LSAD off state.

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7.4.1.2 LSAD standby
In LSAD standby state, the LSAD system shall:

a) Verify that ODD conditions are satisfied to enable a transition to LSAD active state.

b) Perform communications with dispatcher.
c) Remain in standstill.

LSAD standby state may receive an external operating command from the dispatcher selecting the

operating values (e.g. nominal or degraded) for the LSAD system when in DDT state.

Note that nominal mode suggests the ideal performance of the vehicle driven by the LSAD system.

Degraded mode suggests reduced performance on pre-defined vehicle parameters due to external or

the LSAD system’s internal conditions.
7.4.1.3 LSAD active
In LSAD active state, the LSAD shall perform
...

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